Irinotecan/Capecitabine Versus Capecitabine in Patients Treated With A/T for HER2 Negative Metastatic Breast Cancer

Prior to enrollment, patients will be confirmed for hormone and HER2 receptor status. Patients may have either measurable and/or evaluable metastatic lesions which are able to be assessed by chest, abdomen CT and bone scan performed within 28 days prior to start of treatment. * Capecitabine alone arm: 1250 mg/m2, BID, day 1-14, every 3 weeks * Irinotecan plus capecitabine arm : Irinotecan 80 mg/m2, day 1 and 8, every 3 weeks + capecitabine 1000 mg/m2, BID, day 1-14, every 3 weeks. Randomization will be done using a random block size permutation method and stratified based on : hormone receptor status (negative vs. positive), first line vs. more than second lines, visceral metastasis (negative vs. positive). Treatment will continue until disease progression, death, or discontinuation due to side effects of drugs or refusal by patients. The primary objective of this study is to estimate the PFS of capecitabine and irinotecan in patients with anthracycline and taxane- pretreated metastatic breast cancer, which will be estimated by the Kaplan-Meier method and compared by log-rank test. Overall survival will be also estimated by same method. The secondary statistical analysis consisting of an estimation of the complete and partial response rates and response rates of the treatment will be calculated as the ratio of the number of complete and partial responders to the total number of evaluable patients and toxicity profile, which will be estimated as the ratio of the number of occurrence to the total number of evaluable patients. A 95% confidence interval for the response rate is computed based on the binomial distribution function. The analysis for reporting the final treatment results will be undertaken when each patient has been potentially followed for a minimum of 12 months. The overall survival and progression free survival, and their respective medians will be estimated with 95% confidence intervals.